From jop at astro.columbia.edu Mon Sep 6 14:34:30 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 6 Sep 2004 14:34:30 -0400 (EDT) Subject: (cba:news) stars for september Message-ID: Dear CBAers, Sorry for the long silence! I've been on vacation at the Rhode Island shore, and have been dead to email for about 2 weeks. I'm now getting ready to move to Massachusetts, where I'll spend the year on sabbatical. I'll send you new coordinates when I have 'em... but email here at Columbia will work fine. I'm just now digging into the last two weeks of data. But I know enough to make some recommendations re targets for the next month or so. Delete V1315 Aql. The season is getting short, and we have enough. Raise V1101 Aql in priority. Season's kinda short for this star also, but based on its late-season performance last year, I feel sure that it will be a rewarding target (basically with negative superhumps and apparent dwarf-nova outbursts - just the second star known with that combination). AO Psc and FO Aqr remain pretty good targets, for all hemispheres and all observation lengths - because the pulse periods are short, even 1-hour observations have value (although longer is better). There are two new northern stars that are perfectly placed and likely to be superb targets for observation in the next coupla months (starting now). Last year's coverage of LD 317 ("And" in the CV Catalogue) strongly suggested that this is a shiny new DQ Herculis star, with a spin period of 36 minutes. Another season of observation should nail it down, plus provide a long-term ephemeris (for this period and the more obvious orbital period). Well placed, decently bright - fire away! The other is HS 2331+3905, also "And" in the Downes et al. catalogue. This one is considerably fainter, I think around 16.5 most of the time. But it's another star with a fascinating panoply of short periods, apparently representing the orbit and the pulsations of the white dwarf. As you can see from the names, both of these stars are very recent arrivals to the astrophysical scene, with still no "proper publications". Because of its brightness, I'd tend to recommend LD 317 - but both are good targets. Since the Milky Way now rides high in the northern sky, most of the snazzy targets now are northern. Two that aren't are the following... EF Tuc. We got in a good season last year, and we'd like to get one more before going to press. Bright, far southern, eclipsing, superhumping, no previous substantial publications... a great target all around! BW Scl. Very faint, around 17th magnitude. Widely thought to be a dwarf nova, though no dwarf-nova eruption has ever been seen. The real payoff is to see one! But my guess is that they happen very, very raraely - the light curve is reminiscent of WZ Sge. Meanwhile, we can at least track the orbital period very precisely - or those of you can who can work at 16-17 magnitude comfortably. Finally, there's V1101 Aql. I hope that some of you Australites can work on that one as well. With a dec of +15, it should be feasible for some of you... and we are a little more longitude-challenged these days, now that Major Tom has left Uzbekistan... OK, back to the treasures of the last 2-3 weeks of data. Happy observing! joe From jop at astro.columbia.edu Wed Sep 15 17:39:40 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 15 Sep 2004 17:39:40 -0400 (EDT) Subject: (cba:news) Outburst of ASAS 002511+1217.2 = RX J0025.1+1217 (fwd) Message-ID: As some of you have noted, this is really quite a bright dwarf nova, about 10.5 - very surprising that this has eluded discovery until now! Seems likely the outbursts are quite rare, and that makes it our boy! All the more so since the star transits at local midnight and is available to all northerners and intrepid southerners. Great target - let's start a vigorous campaign! joe ---------- Forwarded message ---------- Date: Wed, 15 Sep 2004 17:55:31 +0200 From: Grzegorz Pojmanski To: vsnet-alert at kusastro.kyoto-u.ac.jp Subject: [vsnet-alert 8295] Outburst of ASAS 002511+1217.2 = RX J0025.1+1217 Outburst of ASAS 002511+1217.2 = RX J0025.1+1217 ASAS-3 Alert System has detected outburst of possible dwarf nova: ASAS 002511+1217.2 (00 25 11 +12 17 12, Eqnx 2000), which is close (within one pixel) to the RX J0025.1+1217 X-ray source (00 25 10.9 +12 17 25 Eqnx 2000) and UNSO B1 objects: USNOB_1022-0004645 (00:25:11.14 +12:17:12.3) B1=20.73 B2=16.64 R2=16.98 I2=17.24 USNOB_1022-0004646 (00:25:11.33 +12:17:14.3) B1=17.42 R1=16.46 Observations: V HJD (2450000+) AP_0 AP_1 3254.86329 (invisible) 3259.70301 12.463 10.487 3263.79241 11.074 11.076 3263.79528 11.115 11.101 Please note, that observation on 3254.86329 is 12.463 in aperture AP_0 (2 pixels) and 10.487 10.482 10.462 10.446 in 3,4,5 and 6 pixels diameter apertures. I cannot yet figure out why it is so, but taking into account that larger apertures show consistently 10.4-10.5 the star may have already passed its maximum. Graphical light curves on WWW pages automatically show however AP_0 magnitudes for 3259.70301 and AP_1 magnitudes for 3263.79241 and 3263.79528, suggesting that star may still be rising. There are no previous ASAS observations at this position Light curve and images can be found on http://www.astrouw.edu.pl/cgi-asas/asas_disc/002511+1217.2,3254 or on ASAS Alert pages: http://www.astrouw.edu.pl/~gp/asas/asas.html -> Alert Service Page -> New alerts From jk at cbastro.org Sat Sep 18 23:05:55 2004 From: jk at cbastro.org (Jonathan Kemp) Date: Sat, 18 Sep 2004 23:05:55 -0400 (EDT) Subject: (cba:news) cba lists Message-ID: Hi CBAers, As announced in a recent message and as you have seen in recent posts, we now have a cba-chat list to go along with cba-news. Since we now have a split of the original list of sorts, if you find that you prefer to only receive cba-news and not cba-chat, please send me an e-mail. Additionally, if you have any other subscription queries, you should feel free to e-mail me directly. Also, if you change institutions and/or e-mail addresses, please let me know. I'll happily change your address and it also cuts down on chasing down malfunctioning forward setups and also means that I won't have to manually pipe through any contributions you make to the lists. Lastly, thanks for bearing with us during recent server upgrades. While it was probably transparent to most of you (e-mail services were largely uninterrupted), apologies if you came across some part of the web site that was momentarily down. Cheers, Jonathan CBA Hilo From jop at astro.columbia.edu Tue Sep 21 04:42:58 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 21 Sep 2004 04:42:58 -0400 (EDT) Subject: (cba:news) Late September... Message-ID: Dear CBAers, About to leave on a week's observing run... but I wanted to toss in my two cents worth. You probably saw Berto's announcement of a V4140 Sgr outburst, which could be the long-awaited super. Despite the lateness of the season, this would be a great target for southern CBAers! It's time for V1101 Aql to go gently into that good night, at least for this year. ASAS0025+12 is staging a great, great show, and I recommend it heartily for everyone! This is likely to be the prime star of 2004 (although Var Her set a high standard)... and should survive moderately unfavorable conditions of cloud, declination, and moonlight (most of the time). I'll write again re this and other stuff from AZ... joe From jop at astro.columbia.edu Mon Sep 27 18:45:48 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 27 Sep 2004 18:45:48 -0400 (EDT) Subject: (cba:news) Report from the trenches... Message-ID: Dear CBAers, Well, actually it's the mountaintop... but you know what I mean. In a long streak of unrelentingly beautiful skies, the body feels like it has been beat up and left in the trenches. Good for the soul, though, and good for science. We (Jonathan is here with me) have been observing with the MDM 2.4 m on Kitt Peak. We've spent most of our time on HS2311+3905, a strange 16th magnitude CV that is a cornucopia of periods, mostly noncommensurate and apparently independent. There's something at 3.1 hours, 1.35 hours (very likely orbital), 23 min, 11 min, 5 min, and 1.1 min - plus a slew of harmonics. Gracious! And a daunting challenge for interpretation. Some of these signals are likely to signify pulsation of the underlying white dwarf, and maybe even ALL of 'em are. Anyway, those matters are far down the road. Our run ends tomorrow. This object will be a challenge for you... but so far, Tonny and Lew have submitted data sets that appear to be pretty good - definitely revealing the larger amplitude signals. It will very important to track them through the (northern) fall, to see which ones have long-term coherence. Nice target for scopes of sufficient aperture. Open wide! - leave those filters safely wrapped inside their shipping containers. But ASAS0025+12 is surely the star of the season. We still have almost no data from half the planet (Europe, Africa, Asia) - but with many consecutive nights of 11 hour coverage, alias problems have melted away and the power spectrum revealed in all its glory. Probably second only to WZ Sge in the quality of its time series. Like all DN, the light curve is dominated by very strong signals at the superhump frequency wsh and its harmonics. But because the coverage is so good, you can also see "sidebands" flanking all the superhump frequencies - i.e. at wsh+W, 2wsh+W, 3wsh+W, etc., where W is a constant interpretable as the precession frequency itself (so wsh+W is the underlying orbital frequency). I consider this really, really valuable - because when you know both the superhump and orbital periods, you can learn the mass ratio of the binary (the difference between Psh and Po is a measure of the secondary's gravitational perturbation). One of the hardest things to know about a CV! The perpetrators have been mostly the usual suspects: Lew, Major Tom, Bob Rea, Dave Messier, Brian, Donn, and some potshots from Arto Oksanen, Peter Nelson, Alon Retter, Michael Koppelman, Gianluca Masi - plus really beautiful data from Michael Richmond and Anthony Kroes. If you've been observing the star and would like to receive the full data, ask. Within a few weeks we plan to institute whereby you can retrieve the raw data yourself, with a password (Jonathan will announce this when it's ready). If you'd like the processed data now, just write me. This has been spliced, and normalized to acount for observatory differences. It's the best version to use for period-finding. ASAS0025 is a nice object for learning about period-finding, because it's kind of... well, GAUDY! Should be a good target for at least a week, maybe much longer. Southerners, don't be scared by the declination - we can really use coverage from Australia and Africa. Berto and Greg Bolt have obtained enough data on DV Sco to suggest superhumps, but the star sets so early that period-finding is tricky. Southerners able to observe this star VERY SOON (within a few days I hope) may be able to get enough coverage to patch together a global time series and determine a unique period. Try! LD 317 has come back into the sky. We had a good campaign last year, revealing signals at Porb and two fast periods near 35 minutes. It's getting a little crowded out by the celebrities now transiting near local midnight... but we sure as hell want to do a good campaign on it this year, and this could be a good time to start. Don't have time to discuss other stars. Getting dark soon... and naturally it's clear. joe From jop at astro.columbia.edu Mon Sep 27 22:56:09 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 27 Sep 2004 22:56:09 -0400 (EDT) Subject: (cba:news) Report from the trenches... In-Reply-To: Message-ID: > Is the star you mention: HS 2331+3905 (And) at 23:34:01.55 +39:21:42.9 ?? Yeah, that's the one. Like I say, it's a toughie, but doable. I'm on it two more nights - tonight and tomorrow. After that, it's in the CBA lap - my last observing till January. joe